The presence of a number of medical and health problems can be detected by changes in the eye, including unusual changes in the position, movement and dilation of the eye. For example, it has been found that one of the leading causes of dizziness and balance problems is associated with the vestibular system in the inner ear. The presence of nystagmus (very specific, rapid, involuntary eye movements) during a dizziness attack can suggest to a clinician that there is a vertiginous component to it and the direction of the nystagmus may provide some evidence to a specialist in the field, of more specific information, such as which ear (or which part of the ear) has the active disease.
Dizziness and balance problems constitute a major public health problem. A significant proportion of adults have had an episode of dizziness that occurs with enough intensity or frequency to promote a visit to a physician. It is one of the most difficult complaints for a physician to assess, as dizziness is generally a subjective symptom of potentially numerous causes. Additionally, dizziness is often an episodic symptom, with the frequency of episodes highly variable. As a patient will very rarely have an episode while actually in the clinic, clinicians are frequently forced to rely solely on the patient's (often unintentionally misleading) report of the symptom(s).
Accordingly, accurate diagnosis of balance symptoms is important not only to exclude potentially serious central nervous system causes but to aid successful treatment. Unfortunately diagnosis is sometimes not possible, or is delayed. Studies have shown that general practitioners (GPs) rarely failed to refer urgent cases to specialists but often failed to refer patients with persistent vestibular conditions. Part of the difficulty is that the known apparatus for detecting and recording nystagmus and other eyes movements are large, expensive machines that are only available for use by specialists. Due to the size, complexity and expense of such machines, they are typically limited to laboratory use for specific tests. Such machines are rarely used to monitor patients at the time of a dizziness episode.
The present invention was developed with a view to providing a portable device for the investigation of eye movements that may occur during episodic vertigo and dizziness and a method of conducting the investigation using the device. The device can be used away from the clinic and does not need a specialist to operate it. However it will be understood that the device may also be used more generally in oculography and for investigation of the eye.
References to prior art in this specification are provided for illustrative purposes only and are not to be taken as an admission that such prior art is part of the common general knowledge.